This invention relates to wheelchairs of the type used by invalids and more particularly to wheelchairs which may be folded or collapsed for storage or transportation.
The present public interest in saving fuel is manifested in a trend towards the manufacture of lighter weight more fuel efficient automotive vehicles. Such vehicles of necessity are dimensionally smaller than similar vehicles manufactured in recent prior years, such that trunk storage space and the space within the body of the vehicle are substantially reduced. In many of such smaller vehicles there is insufficient space in the trunk or in the body to accommodate a conventional foldable wheelchair for transportion.
The present state of the art includes a number of foldable chair constructions, each having rigid side frame structural members connected by an appropriate parallelogram linkage arrangement. These frame members may be moved together to reduce the width of the wheelchair but no reduction in the depths of the wheelchairs has been satisfactorily accomplished.
Typical prior art foldable wheelchairs of the above type are described in the following U.S. Pat Nos. 2,133,540; 2,354,949; 2,379,566; 2,665,743 and 2,675,057. A number of attempts have been made to provide both width and depth reduction in a foldable wheelchair. Examples of such constructions may be found in the following U.S. Pat. Nos. 2,896,693; 2,927,631; 3,901,527; 3,968,991; 4,025,088 and 4,045,051. Generally, in each of these constructions, over which the present invention is deemed to be an improvement, some sacrifice in function, economy and simplicity of construction or structural rigidity is experienced, primarily attributable to the elimination of inherently more rigid and lower cost side frame structural members which are characteristic of conventional foldable wheelchairs.